This invention pertains to a reciprocating wiper system for motor vehicles.
German specification OS No. 2,215,307 shows a reciprocating wiper system in which a guide member is driven in pendulum fashion via a wiper shaft. A toothed wheel is rotatably mounted in the guide member. The axis of the wheel does not coincide with the axis of the wiper shaft. A crank is connected to the wheel in a manner protected against twisting. A coupling rod is articulated to the free end of the crank and to a slide which is mounted in the guide member in such a way that it may run linearly in and out radial to the wiper shaft. The movement of the slide is achieved in that the toothed wheel meshes with a stationary crown gear while the guide member is swiveled and the axis of this crown gear coincides with the axis of the wiper shaft.
When a particular tooth of the toothed wheel is in mesh with a predetermined space width of the crown gear, the crank, the coupling rod and the slide are in a predetermined position. When the guide member and the crown gear are mounted, care has to be taken with the position of the gearing elements.
German specification OS No. 2,417,128 shows a reciprocating wiper system in which a toothed wheel mounted in a housing driven in pendulum fashion meshes with a stationary toothed wheel. The toothed wheel moved in pendulum fashion is also connected with a crank in a manner protected against twisting. However the rotary movement of the crank is now transformed to a to-and-fro movement of the slide via a toothed rack, two further toothed wheels and a second toothed rack. As in the wiper system outlined above, care has to be taken when the housing with all gearing elements accommodated therein is mounted on the base plate carrying the stationary toothed wheel, to make certain that the toothed wheel mounted in the housing meshes with the stationary toothed wheel in accordance with the position of the gearing elements.
The same problem arises with the mounting of a reciprocating wiper system described in U.S. Pat. No. 3,003,173 in which along with the toothed wheel that meshes with the stationary toothed wheel in a manner protected against twisting, a further toothed wheel is connected into which engages a slide having a portion formed like a toothed rack. The system of the German Pat. No. 3,125,628, in which the toothed wheel meshing with a stationary crown gear is only an intermediate wheel meshing with a further toothed wheel with which a crank is connected in a manner protected against twisting, entails the same mounting difficulties.